Phenology and Weed Management. John Cardina, Catherine Herms and Dan Herms

Transcription

1 Phenology and Weed Management John Cardina, Catherine Herms and Dan Herms

2 What do we want to predict to aid weed management? When to look When to get ready When to treat When it s too late

3 Growth stages of interest Times of maximum susceptibility to control: * Germination annuals (preemergence control) * Final emergence annuals (post-emergence control) * Low internal energy reserves perennials

4 Goal of prediction Optimum timing for effective management Optimum timing might reduce inputs, cost etc

5 What we know about predicting weed development: Emergence and growth are temperature dependent. Degree-day accumulation varies over space & time. Degree-day and calendar date are poor predictors. Susceptible growth stages difficult to detect & monitor.

6 Cumulative DD50 DD 50 Accumulation by Year Note difference in DD accumulation among years Jan-01 Feb-01 Mar-01 Apr-01 May-01 Jun-01

7 Cumulative DD50 DD 50 Accumulation by Year If 200 DD required for a phenological event, it will occur on different days Jan-01 Feb-01 Mar-01 Apr-01 May-01 Jun-01

8 METHODS: flowering phenology of >80 native and ornamental plant species and/or cultivars 4 individuals of each were monitored 3x weekly * Date of First Bloom * Date of Full Bloom > 200 phenological events These phenological events can be determined with precision.

9 First and Full Bloom First flower bud opens, revealing pistils & stamens 95% of flower buds open (ie. 19 of 20 buds open)

10 Plant taxa include: Acer Aesculus Amelanchier Cercis Crataegus Forsythia Lonicera Magnolia Malus Prunus Pyrus Rhododendron Spiraea Syringa Viburnum Weigela

11 Weed emergence phenology methods Monitored in crop field and lawn environments Weekly emergence counts - March to August Cumulative emergence (%) for each date

12 Estimated date of 25, 50 and 80% emergence two methods:

13 100 Cumulative % Emgergence fit sigmoidal equation to data, then solve Julian Date

14 100 Cumulative % Emgergence linear equation between points (y=m x + b; CE=m PredictedDate + b) Julian Date

15 Cumulative % Emgergence Julian Date For each phenological event (i.e. % emergence) we calculated the required number of degree-days. We then ranked events by DD to produce a biological calendar >> DD 50 :

16 Cumulative % Emgergence % Julian Date Example: Common ragweed 80% emergence average 305 DD DD 50 : 305

17 Put weed emergence events into biological calendar: Species Event DD50 Average Date DD50 Silver Maple first bloom Mar 34 Corneliancherry Dogwood first bloom Mar 40 Silver Maple full bloom Mar 42 Red Maple first bloom Mar 45 Red Maple full bloom Mar 75 Star Magnolia first bloom Mar 83 Border Forsythia first bloom Mar Sargent Crabapple full bloom May 298 Umbrella Magnolia first bloom May 304 Red Horsechestnut first bloom May 304 Common Ragweed 80% May 305 Vanhoutte Spirea first bloom May 309 Common Lilac full bloom May 315

18 Weed Emergence in the Biological Calendar Species Event DD50 Average Date DD50 Norway Maple first bloom Apr 116 Compact Garland Spirea first bloom Apr 159 Common Ragweed 25% Apr 160 Eastern Redbud first bloom Apr 191 Common Ragweed 50% Apr 197 Common Horsechestnut first bloom May 251 Velvetleaf 25% Apr 253 Japanese Flowering Crab full bloom May 254 Lambsquarter 25% Apr 262 Red Buckeye first bloom May 265 Flowering Dogwood first bloom May 268 Eastern Black Nightshade 25% May 282 Wayfaringtree Viburnum full bloom May 290 Giant Foxtail - T1 25% May 294 Red Horsechestnut first bloom May 304 Common Ragweed 80% May 305 Common Lilac full bloom May 315 Redosier Dogwood first bloom May 323 Eastern Black Nightshade 50% May 324 Common Horsechestnut full bloom May 346 Lambsquarter 50% May 362

19 CONTINUED...Weed Emergence in the Biological Calendar Species Event DD50 Average Date DD50 Giant Foxtail - T1 50% May 363 Pagoda Dogwood first bloom May 363 Velvetleaf 50% May 368 Black Cherry first bloom May 368 Ohio Buckeye full bloom May 374 Winter King Hawthorn full bloom May 407 Eastern Black Nightshade 80% May 410 Smokebush first bloom May 505 Velvetleaf 80% May 507 White Fringetree full bloom May 517 Giant Foxtail - T1 80% May 520 Lambsquarter 80% May 529 Black Locust full bloom May 548 Multiflora Rose first bloom May 550 Dandelion 25% May 552 Mountain-laurel first bloom May 565 Smokebush full bloom Jun 611 Dandelion 50% Jun 628 Multiflora Rose full bloom Jun 647 Dandelion 80% Jun 737 Mountain-laurel full bloom Jun 822

20 Possible applications of the biological calendar: Web-based predictions of emergence Local verification with ornamentals When to scout... Optimum time of control...

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22 Smooth Large Digitaria ischaemum Digitaria sanguinalis

23 Smooth Large Digitaria ischaemum Digitaria sanguinalis

24 Smooth Large Digitaria ischaemum Digitaria sanguinalis

25 100 % Cumulative Emergence Large Crabgrass Smooth Crabgrass 0 Apr May Jun Jul Aug Sep Oct 2002

26 100 % Cumulative Emergence % Large Crabgrass Smooth Crabgrass 0 Apr May Jun Jul Aug Sep Oct 2002

27 Day of first and 80% emergence of large and smooth crabgrass in turf environments in Year Species Day of Year First 80% emergence emergence 2002 Large 111 b 183 a Smooth 107 c 166 b 2003 Large 124 a 189 a Smooth 106 b 134 c 2004 Large 119 b 164 b Smooth 115 c 150 b

28 Degree-day models used to predict emergence of large and smooth crabgrass in turf. Percent Emergence Crabgrass species Air temperature models Start Date Base Temp (C) Cumulative DD Soil temperature models Start Date Base Temp (C) Cumulative DD First Large 1-Nov Nov Smooth 1-Nov Mar % Large 1-Nov Nov Smooth 1-Mar Mar Chosen model parameters gave the lowest CV in cumulative growing DD for emergence data collected from 2002 to Air and soil (at 5 cm) temperatures were obtained from a weather station near the study site.

29 Biological calendar of ornamental plant bloom events and first emergence of large and smooth crabgrass at Wooster, Ohio from 2002 to 2004 (DD; 50 F base temperature, January 1 start date). Common Name Bloom or Emergence Event Date DD Red Maple first bloom 20-Mar 49 Star Magnolia first bloom 4-Apr 89 Border Forsythia first bloom 4-Apr 92 Border Forsythia full bloom 13-Apr 105 Saucer Magnolia first bloom 13-Apr 119 Bradford Callery Pear first bloom 15-Apr 137 Star Magnolia full bloom 16-Apr 149 Allegheny Serviceberry first bloom 16-Apr 155 Smooth Crabgrass first emergence 16-Apr 155 PJM Rhododendron first bloom 16-Apr 155 Saucer Magnolia full bloom 18-Apr 184 Allegheny Serviceberry full bloom 18-Apr 187 Bradford Callery Pear full bloom 19-Apr 189 Eastern Redbud first bloom 20-Apr 192 PJM Rhododendron full bloom 20-Apr 201 Large Crabgrass first emergence 24-Apr 211 Snowdrift Crabapple first bloom 21-Apr 213 Common Lilac first bloom 24-Apr 231 Ohio Buckeye first bloom 25-Apr 241

30 Biological calendar of ornamental plant bloom events and 80% emergence of large and smooth crabgrass at Wooster, Ohio from 2002 to 2004 (DD; 50 F base temperature, January 1 start date). Black Locust first bloom 20-May 459 Sweet Mockorange first bloom 23-May 500 Smooth Crabgrass 80% emergence 24-May 548 Arrowwood Viburnum first bloom 27-May 564 Black Locust full bloom 28-May 565 Multiflora Rose first bloom 29-May 588 Washington Hawthorn first bloom 2-Jun 641 Arrowwood Viburnum full bloom 3-Jun 649 Multiflora Rose full bloom 3-Jun 652 Northern Catalpa first bloom 5-Jun 678 Large Crabgrass 80% emergence 6-Jun 692 American Elder first bloom 7-Jun 713 Sweet Mockorange full bloom 9-Jun 733 Washington Hawthorn full bloom 10-Jun 775

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32 25% emerged 80% emerged Photo credits: Janet Sternfeld, Denise Ellsworth First emergence

33 How consistent is the order of weed emergence and flowering events over years for several species?

34 Rank of Phenological Indicator Plants & Crabgrass 200 Phenological indicator plants 1:1 line Large crabgrass Smooth crabgrass 80% % Rank, % 50% 25% 50% 50 1st 1st R 2 = Average Rank, 2002 & 2003

35 Rules for crabgrass control:

36 Rules for crabgrass control: Apply preemergence herbicide when forsythia blooms Apply preemergence herbicide when forsythia starts to bloom Apply preemergence herbicide when forsythia blooms drop

37 Rules for crabgrass control: Apply preemergence herbicide when forsythia blooms Apply preemergence herbicide when forsythia starts to bloom Apply preemergence herbicide when forsythia blooms drop Apply preemergence herbicide when soil temp > 50 F

38 Days delay in crabgrass emergence relative to selected ornamental plant bloom events. Crabgrass Species Ornamental Plant Bloom Event Deviation in Days (emerged Day bloom Day) Large Forsythia First Forsythia Full Eastern redbud First Bradford pear Full Smooth Forsythia First Forsythia Full Saucer magnolia First Bradford pear First Forsythia blooms were frosted out in Higher number => delay in emergence relative to blooming.

39 Delay in emergence of large and smooth crabgrass from dates predicted by rules for when to apply preemergence herbicides for crabgrass control. Delay in emergence (Observed first emergence - predicted PRE Rule 1 apply when soil temperatures at 10-cm depth remain above 10 C for 24 consecutive hours. application) Crabgrass Species days Large Smooth apply when soil temperatures at 2.5- to 5.0-cm depth reach 10 to 12.8 C, or when forsythia is in full bloom. 1 McCarty et al. 2001; 2 Calhoun 2002 Large Smooth

40 Herbicidal activity (crabgrass control) ~ 40 Days Weed emergece

41 IPM Approach to Crabgrass Management Late spring Summer Fall ===> Late fall Allow grass to grow as long as tolerable Mow high to suppress crabgrass seedlings If seed heads form, collect clippings Over - seed weak spots Fertilize only in fall; only if needed

42 Sources of Error in Weed Phenology Prediction Determining first emergence Determining 100% emergence Moisture response of weeds vs ornamentals Weed biotypes? Geographical variation?

43 Why it might be less consistent for weeds: Emergence is final stage of complicated process Loss of dormancy Water absorption Germination Initial seedling growth Emergence Environmental cues Weed seeds & seedlings respond to small zone of soil temperature, not air temperature Seeds on top of soil vs deeply buried

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45 Multiple emergence cohorts Genetically determined

46 2008 Cumulative Emergence of Giant Ragweed in BG Plots 0.6 Cumulative % Emergence ragweed emergence 0.0 CORN BARE 2008 Giant Ragweed in Belowground (count and pull) Plots Mar Apr May Jun Jul Aug No. Emerged Date CORN BARE Three distinct emergence cohorts 2 0 Mar Apr May Jun Jul Aug Date

47 Emergence pattern varies with plant origin.

48 WA Marestail Downy brome F pennycress Shep s purse Wild carrot Relative emergence of common weeds Group 1 G. ragweed kochia P. knotweed Wild mustard Russian thistle White cockle Group 2 Quackgrass Orchardgrass Pa smartweed Lambsquarters wild oats Hairy nightshade Group 4 Giant foxtail Cocklebur Y. nutsedge Group 3 Redroot Smooth pigweed brome C. ragweed Velvetleaf W. buckwheat Group 5 Green foxtail Milkweed Dogbane Barnyardgrass Yellow foxtail W.P. millet Field sandbur Smooth crabgrass Group 7 Fall panicum Large crabgrass Group 6 Morningglories Blk. Jimsonweed Nightshade Witchgrass Shattercane Venice mallow Waterhemp Sm. Groundcherry